mb/asus/kfsn4-dre: Return early if CK804 not found

It probably doesn't make sense to continue if the CK804 isn't found, and
doing so would perform uninitialized reads of the busn and io_base
arrays anyway, so let's return early.

Change-Id: I13c663314496caf51a57da7f27f9ea24e3d7fcbd
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 1370586
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34573
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/mainboard/asus/kfsn4-dre/romstage.c

@@ -132,8 +132,10 @@ static void ck804_control(const unsigned int *values, u32 size,
 		}
 	}
 
-	if (ck804_num < 1)
+	if (ck804_num < 1) {
 		printk(BIOS_WARNING, "CK804 not found at device base unit id %02x!\n", bus_unit_id);
+		return;
+	}
 
 	ck804_early_set_port(ck804_num, busn, io_base);